1. Field of the Invention
This invention relates to an encapsulated medium-voltage electrical load switching apparatus.
2. Description of the Prior Art
Medium-voltage electrical switching installations exist which have an arrangement of switches mounted for operation within an electronegative gas-filled metal housing and gastight fittings connecting the switch arrangement with externally located cables, fuses and switch controls. An electronegative gas, such as sulfur hexafluoride is used to fill the housing. Other electronegative gases, which are commonly understood to be gases which are able to form negative ions by the application of an electron, can also be used. Because of the wide usage of such installations in power distribution systems, important desirable design objectives include low cost, compactness and minimum maintenance requirements. An example prior art mediumvoltage load switching apparatus directed at attaining maintenance-free operation over long periods of time, together with compactness and low manufacturing costs is disclosed in German Offenlegungsschrift DE-OS No. 27 29 571.